FluidicTech
Mechanical
I asked this is question under the mechanical code issues forum. I appreciate the one response I got; however,I was hoping for some more input.
We often butter P1, P4, P5A and P5B base materials when welding them to P8 material to avoid PWHT (of the final joint) of the P8 material. When the design temperature is significantly high, we use Inconel to butter, then heat treat, and then use Inconel filler for the final joint. We currently have processes qualified for buttering with SMAW, heat treating, and completing the joint with GTAW & SMAW. We are looking at qualifying some new procedures that use FCAW or SAW to complete the joint after the buttered material has been heat treated. That is, we would use SMAW to butter (with inconel), send to heat treat, run a tig inconel root pass and use SAW (inconel) to complete the joint.
Paragraph QW-283 of Section IX deals with buttering. All buttering thicknesses are or will be 3/16" or greater. The QA department believes that we can, under QW-283.4(b), qualify a new procedure for the SAW using Inconel plate for the test coupon which matches our Inconel filler, and subsequently qualify all P1-P8, P4-P8, P5A-P8, and P5B-P8 welds at the same time without having to qualify procedures for each of these different base metals. This SAW procedure would be used in conjuction with the inconel SMAW and GTAW procedures we already have. The logic is, that we already have individual "buttering" procedures for P1-P8, P4-P8, P5A-P8, and P5B-P8 welds. Once the P1, P4, and P5 material has been buttered, heat treated, and root pass with these procedures, we can use a single SAW procedure no matter what the original base metal was, because it is now effectively inconel we are joining to the P8.
I interpret paragraph QW-283.4 as stating that if "an essential variable is changed in the portion of the weld to be made after buttering" a new qualification can be made by using inconel plate that matches the filler metal. However, because changing the base metal is an essential variable in the portion of the weld prior to buttering, this is not applicable. Therefore, we would have to qualify a different procedure for each different base metal. And, as the one response I received to this question earlier pointed out, we don't currently have a procedure for welding on the SAW with inconel. Also, our shop will be doing all of the welding.
I am not a Section IX expert, and the QA department has more experience here than I do. But, their interpretation doesn't seem quite right to me. Who is right? Any Section IX welding experts out there?
We often butter P1, P4, P5A and P5B base materials when welding them to P8 material to avoid PWHT (of the final joint) of the P8 material. When the design temperature is significantly high, we use Inconel to butter, then heat treat, and then use Inconel filler for the final joint. We currently have processes qualified for buttering with SMAW, heat treating, and completing the joint with GTAW & SMAW. We are looking at qualifying some new procedures that use FCAW or SAW to complete the joint after the buttered material has been heat treated. That is, we would use SMAW to butter (with inconel), send to heat treat, run a tig inconel root pass and use SAW (inconel) to complete the joint.
Paragraph QW-283 of Section IX deals with buttering. All buttering thicknesses are or will be 3/16" or greater. The QA department believes that we can, under QW-283.4(b), qualify a new procedure for the SAW using Inconel plate for the test coupon which matches our Inconel filler, and subsequently qualify all P1-P8, P4-P8, P5A-P8, and P5B-P8 welds at the same time without having to qualify procedures for each of these different base metals. This SAW procedure would be used in conjuction with the inconel SMAW and GTAW procedures we already have. The logic is, that we already have individual "buttering" procedures for P1-P8, P4-P8, P5A-P8, and P5B-P8 welds. Once the P1, P4, and P5 material has been buttered, heat treated, and root pass with these procedures, we can use a single SAW procedure no matter what the original base metal was, because it is now effectively inconel we are joining to the P8.
I interpret paragraph QW-283.4 as stating that if "an essential variable is changed in the portion of the weld to be made after buttering" a new qualification can be made by using inconel plate that matches the filler metal. However, because changing the base metal is an essential variable in the portion of the weld prior to buttering, this is not applicable. Therefore, we would have to qualify a different procedure for each different base metal. And, as the one response I received to this question earlier pointed out, we don't currently have a procedure for welding on the SAW with inconel. Also, our shop will be doing all of the welding.
I am not a Section IX expert, and the QA department has more experience here than I do. But, their interpretation doesn't seem quite right to me. Who is right? Any Section IX welding experts out there?